1. Technical Field
The present invention relates to a feeding device such as a paper feeding device and a recording device such as an ink jet printer having the feeding device.
2. Related Art
From the past, as disclosed in JP-A-8-91612, a recording device such as a printer includes a paper feeding device (feeding device) which automatically feeds plural sheets of paper placed in a stacked state (overlap state) to a recording portion by separating the paper sheet by sheet so that the recording is continuously performed on the paper (recording medium).
The paper feeding device disclosed in JP-A-8-91612 is equipped with a paper feeding cassette (mounting portion) allowing the plural sheets of paper to be stacked therein, a paper feeding roller delivering the top sheet of paper by a rotation motion thereof while it is in contact with the top sheet of paper from the stack of paper in a feeding direction, and a gate member for preventing the second top sheet (underlying sheet) of paper from being fed in the feeding direction along with the top sheet of paper.
In more detail, the gate member is movably supported so that is can move such that one end thereof serves as a support point and the other end thereof is in contact with the outer circumferential surface of the paper feeding roller at a predetermined pressure due to urging force of a compression spring. At the other end of the gate member, the inclined surface is provided at a position where the leading end of the paper delivered by the paper feeding roller can hit up. Therefore, if the leading end of the paper delivered by the paper feeding roller in the paper feeding direction hits up against the inclined surface, the gate member having the inclined surface pushed by the paper shakes in a direction in which it moves away from the outer surface of the paper feeding roller, while resisting against the urging force of the compression spring, and a gap is formed between the paper feeding roller and the gate member in a size such large as only one sheet of paper can pass. With such an operation, only the top sheet of paper is fed through the gap in the feeding direction. In the case in which double feeding occurs such that the sheet underlying the top sheet of the paper is fed along with the top sheet of paper due to frictional force between the top sheet and the underlying sheet of paper, the underlying sheet of paper is stopped by the inclined surface of the gate member, thus preventing the double feeding.
In such a paper feeding device, the paper feeding roller is typically configured such that the outer surface is made of a soft material, such as rubber, in order to generate frictional force for the delivery of the paper. Accordingly, as disclosed in JP-A-8-91612, if the other end of the gate member pressed up against the paper feeding roller, a problem that the outer surface of the paper feeding roller deforms arises particularly in conditions of high temperature and humidity. Here, the angle of the delivered paper to the inclined surface of the other end of the gate member is important when forming the gap between the gate member and the outer surface of the paper feeding roller, which allows only one sheet of paper to pass through, when the inclined surface of the gate member is shaken du to the being pushed by the paper.
However, there is possibility that the outer surface of the paper feeding roller comes to be dented by the pushing pressure of the gate member, so that the contact angle between the paper and the inclined surface changes. Further, since the gate member rotates around the support point when the gate member is shaken due to being pushed by the paper, the contact angle between the paper and the inclined surface may change if the gate member is vigorously shaken. If the contact angle between the paper and the inclined surface changes, it is impossible to precisely form the gap and double feeding of paper is more likely to occur.
Such a problem commonly arises in feeding devices which feed a plurality of stacked recording media while separating them one by one as well as in the above-mentioned paper feeding device of the printer.